B-Cell Lymphoma in a Harbor Porpoise (Phocoena phocoena) From Washington State, USA
IAAAM 2015
Barry H. Rickman1,2; Stephanie A. Norman1,3*; Matthew Klope1; Susan Berta1; Howard Garrett1; Sandra Dubpernell1; Mary Jo Adams1; Jessie Huggins4; Dyanna Lambourn5; Stephen J. Trumble6
1Central Puget Sound Marine Mammal Stranding Network/Orca Network, Freeland, WA, USA; 2Sound VetPath, Edmonds, WA, USA; 3Marine-Med: Marine Research Epidemiology, and Veterinary Medicine, Bothell, WA, USA; 4Cascadia Research Collective, Olympia, WA, USA; 5Washington Department of Fish and Wildlife, Marine Mammal Investigations, Lakewood, WA, USA; 6Department of Biology, Baylor University, Waco, TX, USA
Abstract
A fresh dead, female harbor porpoise (Phocoena phocoena) with no overt signs of injury was reported at Maxwelton Beach, South Whidbey Island on 1 November 2013. The porpoise was collected, placed on ice, and transported for a post-mortem examination to be performed by members of the Central Puget Sound Marine Mammal Stranding Network. Diagnosis was based on gross, histopathologic, and immunohistochemical studies. On gross examination, the lymphoma infiltrated the lung and mediastinal lymph nodes. Histopathology revealed a diffuse proliferation of large, atypical polymorphic neoplastic round cells. Positive immunohistochemistry with an anti-CD79a antibody marker confirmed this neoplasm to be of B-cell origin. This neoplasm is classified as a high-grade B-cell lymphoma due to the marked pleomorphism and high mitotic rate. Tissues from the mother were analyzed for persistent organic pollutants (PCBs, DDT/DDE, PBDEs) as well as hormones related to stress in mammals (corticosterone) and compared to a non-diseased adult pregnant harbor porpoise that died as a consequence of fishery interactions. Cortisol levels (ng/g of PP13 blubber/liver homogenate) in the lymphoma porpoise were 23,241.5/916.7 compared to 551.7/65.2 in the control animal. This is the first description of lymphoma in a harbor porpoise as well as in any species of porpoise. Future diagnostics will include comparing contaminant load in this animal to other harbor porpoises in the region and potentially performing additional immunophenotyping and molecular diagnostics (i.e., PCR) to further characterize the tumor type.
Acknowledgements
The authors wish to thank the volunteers of the Central Puget Sound Marine Mammal Stranding Network who assisted with collection of the porpoise samples and to Rebel Sanders for running the corticosterone assays.
* Presenting author